Did a small test today with baudrates higher than 115200 - Fast communication to PC with low Arduino footprint - #12 by robtillaart - Networking, Protocols, and Devices - Arduino Forum -
WINDOWS 7 64 bit IDE22 putty.exe <--> Arduino 2009
Certainly not extensive tested but the results looked promissing enough to ask for support for the following baudrates in the Serial Monitor in a next version of the IDE
- 230400 (twice current max speed)
- 345600 (triple current max speed)
The fact that the higher non standard speeds of 400K and 500K worked relatively well, gives some copnfidence that these two "lower" speeds are robust enough.
Especially for "real time" apps speed is allways usefull.
Rob
-- update --
Had few sketches running for about 3 weeks at 230400 and one at 345600 (both 2009 and UNO).